title: Rapid detection of multidrug-resistant Mycobacterium tuberculosis by multiplex allele-specific polymerase chain reaction.
abstract: METHODS
  Dr Cetrangolo Hospital, Buenos Aires Province, Argentina.
  
  
  OBJECTIVE
  To evaluate a multiplex allele-specific polymerase chain reaction (MAS-PCR) to detect multidrug-resistant tuberculosis (MDR-TB) clinical isolates and to describe the main mutations conferring resistance to isoniazid (INH) and rifampicin (RMP).
  
  
  METHODS
  Drug-resistant Mycobacterium tuberculosis clinical isolates were tested to detect mutations using MAS-PCR. The genes involved were katG, inhA promoter and rpoB.
  
  
  RESULTS
  Among 193 clinical isolates included in the study, 52.6% of the INH-resistant isolates presented a mutation in the katG (315) gene, 28.1% in the inhAP (-15) and 3.0% in both. For the rpoB gene, 60% of the RMP-resistant isolates showed a mutation in codon 531, 17.5% in 526 and 2.5% in 516. Results were compared with those obtained by sequencing, and 100% concordance was obtained for the detection of the mutation in katG (315), 94.1% for inhAP (-15), and 97.8% for rpoB. The global concordance between both methods was 98%.
  
  
  CONCLUSIONS
  The MAS-PCR system allowed the simultaneous and rapid detection of approximately 80.0% of the drug-resistant clinical isolates. This method could be used as a rapid and simple screening tool to detect drug-resistant TB in clinical practice.
authors.affiliation: Reference Laboratory, Tuberculosis Control Program of Buenos Aires Province, Buenos Aires, Argentina. belen_imperiale@yahoo.com.ar
authors.forename: B R
authors.initials: BR
authors.lastname: Imperiale
authors.forename: A A
authors.initials: AA
authors.lastname: Cataldi
authors.forename: N S
authors.initials: NS
authors.lastname: Morcillo
mesh_terms: D000483:Alleles; D000995:Antitubercular Agents / Q000494:pharmacology*; D001118:Argentina; D024901:Drug Resistance, Multiple, Bacterial; D005798:Genes, Bacterial; D006801:Humans; D007538:Isoniazid / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D009154:Mutation; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D016133:Polymerase Chain Reaction / Q000379:methods*; D012293:Rifampin / Q000494:pharmacology
chemical_list: D000995:Antitubercular Agents; D007538:Isoniazid; D012293:Rifampin